JP2015082230A - Drive support device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive support device which can realize proper drive support even when a sensing distance of an ultrasonic sensor is extended.SOLUTION: A drive support device includes: an ultrasonic sensor which transmits an ultrasonic wave toward an object outside a vehicle and acquires object information on the distance to the object on the basis of a reflection wave of the ultrasonic wave; and a processing unit which permits first driving force restriction control when the distance to the object is equal to or greater than a prescribed distance on the basis of the object information from the ultrasonic sensor and permits at least one of second driving force restriction control having the higher degree of restriction than the first driving force restriction control and intervention brake control when the distance to the object is smaller than the prescribed distance.

Description

  The present disclosure relates to a driving support apparatus using an ultrasonic sensor.

  2. Description of the Related Art Conventionally, an obstacle detection device that compares a threshold value used for determining the presence or absence of an obstacle with a signal obtained by amplifying a received wave of an ultrasonic sonar (ultrasonic sensor) with a predetermined gain is known (for example, patent Reference 1).

JP 2007-333609

  By the way, in general, an ultrasonic sensor has a shorter sensing distance than a radar sensor using radio waves (for example, millimeter waves) or light waves (for example, lasers). For this reason, it is effective to increase the sensing distance of the ultrasonic sensor in order to appropriately execute the intervention braking control (or the driving force limitation) based on the object information by the ultrasonic sensor. However, when the sensing distance of the ultrasonic sensor is increased, the detection area is widened. However, there is a possibility that even a non-detection target object that cannot be detected before the expansion is detected.

  Therefore, an object of the present disclosure is to provide a driving support device that can realize appropriate driving support even when the sensing distance of an ultrasonic sensor is increased.

  According to one aspect of the present disclosure, a driving support device capable of realizing appropriate driving support even when the sensing distance of an ultrasonic sensor is increased is provided.

According to the present disclosure, an ultrasonic sensor that transmits ultrasonic waves toward an object outside the vehicle and acquires object information related to a distance to the object based on the reflected wave;
When the distance to the object is greater than or equal to a predetermined distance based on the object information from the ultrasonic sensor, the first driving force restriction control is permitted, while the distance to the object is smaller than the predetermined distance Is provided with a processing device that permits at least one of the second driving force limiting control and the intervention braking control that are higher in the degree of limitation than the first driving force limiting control.

It is a block diagram which shows an example of the system configuration | structure containing the driving assistance device 1 by one Example. It is a figure which shows roughly an example of the detection area | region of the right and left clearance sonars 201a and 201b for a front object detection. It is explanatory drawing of expansion of the detection area (expansion of sensing distance) of right and left clearance sonar 201a and 201b for front object detection. 3 is a flowchart illustrating an example of processing executed by a driving support ECU 10; It is a figure which shows an example of the setting method of predetermined distance (alpha). 7 is a flowchart illustrating another example of processing executed by the driving support ECU 10. It is explanatory drawing of the calculation principle of a horizontal direction distance. It is explanatory drawing of an example of the calculation method of the detection level of the horizontal direction distance of an object.

  Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram illustrating an example of a system configuration including a driving support device 1 according to an embodiment.

  In FIG. 1, the driving support device 1 includes a driving support ECU 10. The driving support ECU 10 is configured by a microcomputer and includes, for example, a ROM that stores a control program, a readable / writable RAM that stores calculation results, a timer, a counter, an input interface, an output interface, and the like.

  Note that the function of the driving support ECU 10 may be realized by arbitrary hardware, software, firmware, or a combination thereof. For example, any part or all of the functions of the driving assistance ECU 10 may be realized by an application-specific integrated circuit (ASIC) or a field programmable gate array (FPGA) for a specific application. Further, part or all of the functions of the driving assistance ECU 10 may be realized by another ECU (for example, a clearance sonar ECU 20). Further, the driving assistance ECU 10 may realize part or all of the functions of another ECU (for example, the clearance sonar ECU 20).

  A clearance sonar ECU (hereinafter referred to as a clearance sonar ECU) 20, clearance sonars 201a, 201b, 201c, 201d, a G sensor 30, a steering angle sensor 40, a meter computer 50, an engine ECU 60, a brake ECU 70, and the like are connected to the driving assistance ECU 10. It's okay. For example, the driving assistance ECU 10 may be communicably connected to the clearance sonar ECU 20, the G sensor 30, the rudder angle sensor 40, the meter computer 50, the engine ECU 60, and the brake ECU 70 by a CAN (Controller Area Network), a direct line, or the like.

  The clearance sonars 201a, 201b, 201c, and 201d are ultrasonic sensors and are provided at appropriate locations on the vehicle body. The clearance sonars 201a, 201b, 201c, and 201d are examples of ultrasonic sensors that detect the presence or absence of a relatively close object having a detection distance of, for example, several centimeters to several meters, or the distance to the object. In the illustrated example, two clearance sonars 201a and 201b are provided on the front bumper, and two clearance sonars 201c and 201d are provided on the rear bumper. However, the number and arrangement of the sensors are not limited to the illustrated example, and for example, four sensors may be provided on the front, four on the rear, and two on the side. The clearance sonars 201a to 201d output detection results (object information) in the respective detection ranges to the clearance sonar ECU 20, respectively.

  The clearance sonars 201a, 201b, 201c, and 201d may operate while the vehicle speed is in a low speed region that is greater than zero. Further, the clearance sonars 201a and 201b for detecting the front object operate when traveling in the forward drive range (for example, the D range), and the clearance sonars 201c and 201d for detecting the rear object are operated when traveling in the reverse range (during reverse). ).

  The clearance sonar ECU 20 processes the detection results input from the clearance sonars 201a to 201d and calculates a “target distance” that is a distance to the object. The clearance sonar ECU 20 transmits the calculated target distance information (distance information) to the driving support ECU 10. For example, the clearance sonar ECU 20 may measure the target distance by measuring the time until the ultrasonic wave irradiated from the clearance sonar is reflected by the object and the reflected wave returns. When the detection angle of the clearance sonar is wide, the direction of the object is not specified only by the detection result from the single clearance sonar. However, the clearance sonar ECU 20 may specify the distance in the lateral direction of the object (the distance in the lateral direction of the object based on the traveling direction of the vehicle) by obtaining the target distance from the plurality of clearance sonars. Further, the shape of the object (for example, a shape like a wall or a shape like a utility pole) may be determined. The lateral distance specifying (calculating) method is arbitrary, but may be a method using triangulation, for example (see FIG. 7).

  The G sensor 30 measures the acceleration in the front-rear direction of the vehicle, and transmits the measurement result to the driving support ECU 10 as “vehicle front-rear G” information. The acceleration in the front-rear direction of the vehicle measured by the G sensor 30 is the total value of the acceleration calculated from the wheel speed and the acceleration of gravity due to the road inclination (vehicle inclination). Therefore, the inclination of the road can be measured by subtracting the acceleration calculated from the wheel speed from the vehicle longitudinal G measured by the G sensor 30.

  The steering angle sensor 40 detects the steering angle of the steering wheel and transmits it to the driving support ECU 10 as steering angle information.

  The meter computer 50 is connected to a combination meter device (not shown) for notifying the driver by display, an alarm sound generator (not shown) for notifying the driver by voice, and the like. . The meter computer 50 controls numerical values, characters, figures, indicator lamps, and the like displayed on the combination meter device in response to a request from the driving support ECU 10, and also generates alarm sounds and alarm sounds to be notified by the notification sound generator. Take control.

  The engine ECU 60 controls the operation of an engine that is a driving source of the vehicle, and controls, for example, ignition timing, fuel injection amount, and the like. The engine ECU 60 controls the engine output based on a requested driving force from a driving support ECU 10 described later. In the case of a hybrid vehicle, the engine ECU 60 may control (suppress) the driving force in accordance with the required driving force from the driving support ECU 10 in cooperation with the hybrid ECU that controls the hybrid system. In the case of a hybrid vehicle or an electric vehicle, the motor output may be controlled based on the required driving force from the driving support ECU 10.

  Further, the engine ECU 60 may transmit information on the accelerator pedal operation, information on the accelerator pedal opening rate, and shift position information to the driving support ECU 10. The information on the accelerator pedal operation is information representing the amount of operation of an accelerator pedal (not shown), and the information on the accelerator pedal opening rate is information representing the accelerator opening. The shift position information is information representing the position of the shift lever, and is P (parking), R (reverse), N (neutral), D (drive), or the like. The information on the accelerator pedal operation may be acquired directly from the accelerator position sensor. Further, the shift position information may be acquired from an ECU that controls the transmission, or may be directly acquired from a shift position sensor.

  The brake ECU 70 controls the braking device of the vehicle. For example, the brake ECU 70 controls a brake actuator that operates a hydraulic brake device disposed on each wheel (not shown). The brake ECU 70 controls the output (wheel cylinder pressure) of the brake actuator based on the required braking force from the driving support ECU 10 described later. The brake actuator may include a pump that generates high-pressure oil (and a motor that drives the pump), various valves, and the like. The hydraulic circuit configuration of the braking device is arbitrary. The hydraulic circuit of the braking device may be configured to be able to increase the wheel cylinder pressure regardless of the driver's depression amount of the brake pedal, and is typically a high pressure hydraulic source other than the master cylinder (a pump that generates high pressure oil). Or an accumulator). Further, a circuit configuration typically used in a brake-by-wire system represented by ECB (Electric Control Braking system) may be adopted. In the case of a hybrid vehicle or an electric vehicle, the motor output (regenerative operation) may be controlled based on the required braking force from the driving support ECU 10.

  Further, the brake ECU 70 may transmit brake pedal operation information and wheel speed information to the driving support ECU 10. The wheel speed information may be based on, for example, a signal from a wheel speed sensor provided on each wheel (not shown). The vehicle speed (vehicle speed) and acceleration / deceleration can be calculated from the wheel speed information. The brake pedal operation information may be obtained directly from the brake pedal force switch or the master cylinder pressure sensor. Similarly, the wheel speed information (or vehicle speed information) is directly from the wheel speed sensor or the drive shaft rotation sensor. May be acquired.

  The driving assistance ECU 10 includes an ICS application (Intelligent Clarence Sonar application) 100. In the illustrated example, the ICS application 100 is software that operates on the driving support ECU 10, and includes an input processing unit 101, a vehicle state estimation unit 102, an obstacle determination unit 103, a control amount calculation unit 104, and an HMI (Human Machine Interface) calculation. Unit 105 and an output processing unit 106.

  Based on the information from the clearance sonar ECU 20, the driving assistance ECU 10 performs driving assistance so that the own vehicle does not collide with the obstacle to be detected. Driving support includes an alarm (cooperation with the meter computer 50) that prompts the driver to perform an independent brake operation, suppression of driving force through intervention (cooperation with the engine ECU 60), and generation of braking force through intervention (braking) Cooperation with the ECU 70). The suppression of the driving force may be realized by an arbitrary method. For example, the suppression of the driving force may be realized by limiting the fuel injection amount, limiting (for example, closing) the throttle opening, and the like.

  The input processing unit 101 performs input processing of various information received by the driving support ECU 10. For example, information received according to the CAN communication standard is converted into information that can be used by the ICS application 100. The input processing unit 101 may receive distance information from the clearance sonar ECU 20, information on the vehicle longitudinal G from the G sensor 30, steering angle information from the steering angle sensor 40, and the like. The input processing unit 101 also receives information on the accelerator pedal operation, information on the accelerator pedal opening rate, and shift position information from the engine ECU 60, and further receives information on the brake pedal operation and wheel speed from the brake ECU 70. Is entered.

  The vehicle state estimation unit 102 has a function of estimating the vehicle state based on the various information input to the input processing unit 101. For example, the vehicle state estimation unit 102 may determine whether or not a vehicle state in which the clearance sonars 201a to 201d should operate is formed.

  The obstacle determination unit 103 determines whether an object detected by the clearance sonars 201a to 201d is an obstacle to be detected based on the target distance received from the clearance sonar ECU 20 (obstacle determination). This is because each piece of object information detected by the clearance sonars 201a to 201d may be generated due to the presence of noise or an object that cannot become an obstacle (for example, an inclined wall on the side of a road described later). Because there is. The obstacle determination may be performed independently on the object information relating to each of the clearance sonars 201a to 201d. Alternatively, for example, an object in front of the vehicle may be executed using object information relating to the clearance sonars 201a and 201b for detecting the front object. A specific example of the obstacle determination method by the obstacle determination unit 103 will be described later.

  Based on the information from the obstacle determination unit 103, the control amount calculation unit 104 calculates a control amount for driving assistance. At this time, the control amount calculation unit 104 varies the control mode of driving assistance based on the information (determination result) from the obstacle determination unit 103. A specific example of the control mode of driving assistance will be described later.

  The HMI calculation unit 105 is a calculation unit for outputting various types of information for alerting the driver to an obstacle when an obstacle to be detected is detected. The HMI calculation unit 105 performs calculation for notifying the driver by a display device, a sound device, a vibration device, or the like (not shown) through the meter computer 50, for example.

  The output processing unit 106 outputs the control amount (required driving force and required braking force) calculated by the control amount calculating unit 104 and the calculation result (output information) calculated by the HMI calculating unit 105 to the engine ECU 60, the brake ECU 70, and the meter. In order to transmit to the computer 50, for example, the signal is converted into a signal according to the CAN communication standard and output.

  FIG. 2 is a diagram schematically showing an example of detection areas of the left and right clearance sonars 201a and 201b for detecting a front object.

  In the example shown in FIG. 2, the left and right clearance sonars 201a and 201b have detection areas D1 and D2, respectively. The detection areas D1 and D2 may be bilaterally symmetric with respect to the longitudinal center axis of the vehicle. As shown in FIG. 2, the detection areas D1 and D2 preferably have an overlapping area D3 in the vehicle front direction. In this case, as will be described later, the lateral distance of the object can be calculated from distance information based on detection results from both the left and right clearance sonars 201a and 201b. Note that the lateral width of the overlapping region D3 may be smaller than the vehicle width.

  FIG. 3 is an explanatory view of the enlargement of the detection area of the left and right clearance sonars 201a and 201b (expansion of the sensing distance) for front object detection, (A) shows the case where the sensing distance is relatively short, (B ) And (C) show a case where the sensing distance is relatively long (when the sensing distance is expanded).

  The sensing distance of the left and right clearance sonars 201a and 201b is preferably set relatively long (for example, 3.5 m or more, preferably 4 m or more) as shown in FIG. Thereby, compared with the example shown in FIG. 3A, the obstacle P1 in the front direction of the vehicle can be detected at an early stage, and the start timing of the driving assistance is advanced to reduce the possibility of collision with the obstacle. be able to.

  In the example shown in FIG. 3B, there are side walls (hereinafter referred to as inclined walls) P2 on both sides in front of the vehicle. The inclined wall is inclined in such a manner that, when viewed from above, the width of the front side of the vehicle (the width between the walls) is wider than the depth side. An inclined wall may exist in the entrance of a bridge, the tunnel below a highway, etc., for example. The width between the inclined walls P2 (lateral width) is slightly larger than the vehicle width, and the vehicle can pass therethrough. When the sensing distance is increased as shown in FIG. 3B, there is a possibility that even the non-detected target inclined wall P2 as shown in FIG. 3C may be detected.

  Below, the structure which enables the passage of a narrow road like this between the inclined walls P2 is mainly demonstrated, expanding the detection area | region of the right and left clearance sonars 201a and 201b.

  FIG. 4 is a flowchart illustrating an example of processing executed by the driving support ECU 10. The processing routine shown in FIG. 4 may be executed at predetermined intervals during the operation of the clearance sonars 201a to 201d. For example, the clearance sonars 201a to 201d may be ones that perform only the clearance sonar on the traveling direction side and perform sound wave transmission / reception processing at predetermined intervals while the vehicle speed is in a low speed region greater than zero. The processing routine shown in FIG. 4 may be executed independently for the distance information related to each of the clearance sonars 201a to 201d, or may be executed collectively. Below, the process performed with respect to the distance information of the clearance sonar 201b is demonstrated supposing the case where the vehicle is moving forward as an example. Similar processing may be executed in parallel for the clearance sonar 201a.

  In step 402, the obstacle determination unit 103 determines whether an object is detected based on distance information from the clearance sonar ECU 20 (distance information related to the clearance sonar 201b). When no object is detected, the distance information from the clearance sonar ECU 20 is not substantially supplied. If an object has been detected in the previous cycle, temporary distance information may not be detected due to noise or the like even though the object is still present in the region to be detected. Accordingly, even when temporary non-detection of distance information occurs, it may be determined that an object is detected. That is, once an object is detected, it may be determined that the object is detected until the object is not detected continuously for a predetermined period or longer. If an object has been detected, the process proceeds to step 404. Otherwise, the process proceeds to step 412.

  In step 404, the obstacle determination unit 103 determines whether or not the object detection level is greater than the specified value Th1. The specified value Th1 may correspond to the maximum value of the detection level range of the object that can be taken due to noise that is not the object to be detected, and may be adapted by testing, analysis, or the like. The object detection level may be a reflected wave level. Alternatively, the object detection level may be an index value indicating the time continuity of object detection. That is, the index value may be an index value indicating how long the object is detected by the clearance sonar 201b. The index value may be, for example, an integrated value of the time when the object is detected by the clearance sonar 201b. For example, if an object starts to be detected from a certain period T0 and then continues to be detected for five consecutive periods up to the current period T4, the index value may be 5T (T is equal to one period) time). In this case, when the object is temporarily not detected in a certain cycle, the index value may be reset to 0, or the time corresponding to the cycle in which the object is not detected may be subtracted. The index value may be the number of periods in which the object is detected by the clearance sonar 201b. For example, if the object starts to be detected from a certain period T0 and then continues to be detected for five periods until the current period T4, the index value may be 5. Also in this case, when the object is temporarily not detected in a certain period, the index value may be reset to 0, or the number of periods that are no longer detected may be subtracted. When the state in which no object is detected continues for a predetermined period or longer, it may be considered that the object has not been detected (in this case, the index value is 0, and even if the same object starts to be detected thereafter). , Treated as a new object). In a simple example, the index value may be a binary value indicating whether or not an object has been detected by the clearance sonar 201b continuously for a predetermined time or more.

  In step 404, if the object detection level is greater than the specified value Th1, the process proceeds to step 406. Otherwise, the process proceeds to step 412.

  In step 406, the obstacle determination unit 103 determines whether the target distance is smaller than the predetermined distance α based on distance information from the clearance sonar ECU 20 (distance information related to the clearance sonar 201b). The predetermined distance α is smaller than the sensing distance of the clearance sonar 201b. An example of a method for setting the predetermined distance α will be described later. If the target distance is smaller than the predetermined distance α, the process proceeds to step 408. Otherwise, the process proceeds to step 410.

  In step 408, the obstacle determination unit 103 permits all of the first driving force limit control, the second driving force limit control, and the intervention braking control. Thereby, 1st driving force restriction | limiting control, 2nd driving force restriction | limiting control, and intervention braking control are performed as needed. The first driving force limiting control is driving force limiting control having a lower degree of limitation than the second driving force limiting control. For example, the first driving force limit control may be a control for setting a predetermined first upper limit value for the driving force request calculated according to the accelerator operation by the user. In this case, the second driving force limiting control may be control for setting a second upper limit value lower than a predetermined first upper limit value. The second upper limit value may be 0. In this case, the second driving force limit control is a control (power cut) for fully closing the throttle opening. The second driving force limiting control may be control that gradually reduces the throttle opening to the fully closed position.

  When the intervention braking control is permitted, the control amount calculation unit 104 determines whether or not the detected object (obstacle) is likely to collide with the host vehicle (whether the object should avoid collision by driving assistance). Or not). For example, the control amount calculation unit 104 is based on the object information related to the object detected by the clearance sonar 201b, the steering angle information received from the steering angle sensor 40, the wheel speed information received from the brake ECU 70, etc. When the target distance is less than the predetermined distance, the vehicle speed is equal to or higher than the predetermined value (or the required deceleration is equal to or higher than the predetermined threshold), and the object is located in a range that cannot be avoided by the steering operation. It may be determined that the own vehicle collides against the object. Note that the steering angle information may not be taken into consideration. When it is determined that the host vehicle collides with the object, the control amount calculation unit 104 calculates the deceleration (target deceleration) necessary to avoid the collision with the object, and requests according to the target deceleration. Calculate the braking force.

  In addition, execution of intervention braking control may be accompanied by execution of 2nd driving force restriction | limiting control (for example, power cut). At this time, the second driving force limiting control may be started at the start of execution of the intervention braking control, or may be executed prior to the execution of the intervention braking control.

  In step 410, the obstacle determination unit 103 permits only the first driving force limiting control among the first driving force limiting control, the second driving force limiting control, and the intervention braking control. Thereby, only the first driving force limiting control is executed as necessary.

  In step 412, the obstacle determination unit 103 prohibits all of the first driving force limit control, the second driving force limit control, and the intervention braking control. In this case, the function of the control amount calculation unit 104 may be substantially stopped. If all of the first driving force limiting control, the second driving force limiting control, and the intervention braking control are already prohibited at the start of the current processing cycle, the processing of the current cycle is terminated as it is. That is, at the start of the current processing cycle, all of the first driving force limit control, the second driving force limit control, and the intervention braking control or only the first driving force limit control is performed by the processing of step 408 or step 410 of the previous cycle. Is permitted, the permission state is switched to the prohibition state.

  According to the process shown in FIG. 4, as described above, when the object detection level is larger than the specified value Th1 and the target distance is smaller than the predetermined distance α, the first driving force limiting control and the second driving are performed. Force limit control and intervention braking control are all permitted. Further, when the object detection level is greater than the specified value Th1 and the target distance is equal to or greater than the predetermined distance α, only the first driving force restriction control is permitted. Further, when the object is not detected or when the detection level of the object is equal to or less than the specified value Th1, all of the first driving force limit control, the second driving force limit control, and the intervention braking control are prohibited.

  Therefore, according to the process shown in FIG. 4, even when the sensing distance of the clearance sonar 201b is larger than the predetermined distance α, appropriate driving support can be realized. Specifically, for an object detected in a range separated by a predetermined distance α or more, if the detection level is larger than a specified value Th1, the first driving force limit control is permitted, thereby providing driving support early. Can start. In addition, the second driving force limiting control and the intervention braking control can be executed for an object detected in a range less than the predetermined distance α, and the possibility of a collision with the object can be reduced. In addition, the second driving force limit control and the intervention braking control are not permitted for an object detected in a range separated by the predetermined distance α or more even if the detection level is larger than the specified value Th1, and therefore the inclined wall P2 ( The traffic between narrow roads that can be passed as shown in FIG. 3C is not hindered (this will be described below with reference to FIG. 5).

FIG. 5 is a diagram illustrating an example of a method for setting the predetermined distance α. FIG. 5 shows a scene (road environment) in which two inclined walls P2 (1) and P2 (2) exist side by side in front of the left side of the host vehicle. In addition, the inclined wall P2 may exist symmetrically also on the right front side of the own vehicle. Although the left clearance sonar 201b is focused here, the same applies to the right clearance sonar 201a. In FIG. 5, the end portion E (back end portion) of the inclined wall P2 (1) on the near side is the center in the left-right direction of the front portion of the host vehicle, the vehicle lateral direction is the X direction, When the direction is the Y direction, it is located at (X1 [m], Y1 [m]). For example, the inclined walls P2 (1) and P2 (2) have an inclination of 45 degrees. The circle C1 is a part of a circle whose radius is the predetermined distance α, and the predetermined distance α corresponds to √ (X1 ² + Y1 ² ).

  In general, the reflected wave that is received with the highest sensitivity by the clearance sonar 201b is a reflected wave that is reflected in a direction orthogonal to the inclined wall P2. That is, the direction in which sound waves are most reflected is a direction orthogonal to the inclined wall P2. In FIG. 5, a straight line extending from the clearance sonar 201b in a direction orthogonal to the inclined wall P2 is indicated by a symbol Q. Therefore, while the straight line Q intersects the inclined wall P2 (1) on the near side, the inclined wall P2 (1) is detected by the clearance sonar 201b. When the vehicle advances from the position shown in FIG. 5 (moves upward in FIG. 5) and the straight line Q passes through the end E of the inclined wall P2 (1) on the near side, the straight line Q becomes the inclined wall P2 ( 1), the inclined wall P2 (1) is not detected by the clearance sonar 201b. Instead, the straight line Q starts to intersect with the back-side inclined wall P2 (2), and the back-side inclined wall P2 (2) starts to be detected by the clearance sonar 201b. This is because the target distance does not become smaller than the predetermined distance α (therefore, the second driving force limiting control and the intervention braking control are not executed), and passes through the side of the inclined wall P2 (1) on the near side. Means that you can. That is, the point shown in FIG. 5 is a point where the front side inclined wall P2 (1) is not detected when the vehicle moves forward from this point, and therefore the target distance related to the front side inclined wall P2 (1). Is the minimum (predetermined distance α). Similarly, the vehicle can pass through the side of the rear inclined wall P2 (2).

  In this way, by setting the predetermined distance α in accordance with the form (inclination angle and end position) of the inclined wall P that can be passed, the passage between the inclined walls P is controlled by the second driving force limit control and the intervention. This is possible without being obstructed by the braking control. In the example shown in FIG. 5, an inclined wall having a general inclination angle (45 degrees) is assumed. However, when the inclination angles of the inclined walls are different, a predetermined distance α may be set according to the inclination angle. . For the position (X1, Y1) of the end portion of the inclined wall P, the predetermined distance α may be set based on the minimum value (or average value) of the possible range of the distance between the inclined walls that can pass. . For example, if the distance between the inclined walls is 3.4 [m], (X1, Y1) = (1.7, 1.4), and the predetermined distance α≈2. A predetermined margin may be set for the predetermined distance α.

  In the example shown in FIG. 5, when a front wall in the vehicle front direction exists instead of the inclined wall P2 (1), the direction orthogonal to the front wall is the front direction (Y direction) of the clearance sonar 201b. . In this case, even if the distance from the front wall becomes smaller than the predetermined distance α, the front wall continues to be detected by the clearance sonar 201b because the front wall exists in the front direction of the clearance sonar 201b. Therefore, in the case of the front wall, the second driving force limiting control and the intervention braking control can be executed, and the possibility of a collision with the front wall can be reduced.

  FIG. 6 is a flowchart illustrating another example of processing executed by the driving support ECU 10. The process shown in FIG. 6 is mainly different from the process shown in FIG. 4 in that step 605 is added. In the following, mainly different parts will be mainly described.

  The processing itself of steps 602, 604, 606 to 612 may be the same as the processing of steps 402, 404, 406 to 412 shown in FIG. If an affirmative determination is made in step 604, the process proceeds to step 605.

  In step 605, the obstacle determination unit 103 determines whether or not the detection level of the lateral distance of the object is greater than the specified value Th2. The prescribed value Th2 may correspond to the minimum value of the detection range of the lateral distance in the case of an obstacle in the front direction (an obstacle that cannot pass), and may be adapted by testing, analysis, or the like. The detection level of the lateral distance may be an index value indicating the time continuity of detection of the lateral distance. That is, the index value may be an index value indicating how long the lateral distance is detected (calculated) continuously based on information from the clearance sonars 201a and 201b. The index value may be, for example, an integrated value of time when the lateral distance is detected. For example, when the lateral distance related to a certain object starts to be detected from a certain period T0 and then continues to be detected for 5 consecutive periods up to the current period T4, the index value May be 5T (T is the time for one cycle). In this case, when the lateral distance related to the object is temporarily not detected in a certain cycle, the index value may be reset to 0, or the time corresponding to the cycle in which the object is not detected may be subtracted. (See FIG. 8). The index value may be the number of periods in which the lateral distance related to the object is detected based on information from the clearance sonars 201a and 201b. For example, when the lateral distance related to a certain object starts to be detected from a certain period T0 and then the lateral distance related to the object continues to be detected for five consecutive periods up to the current period T4, the index value is It may be 5. Also in this case, when the lateral distance related to the object is temporarily not detected in a certain cycle, the index value may be reset to 0, or the number of cycles that are not detected may be subtracted. In a simple example, the index value may be a binary value indicating whether or not the lateral distance is detected continuously for a predetermined time or longer.

  In step 605, if the detection level of the lateral distance of the object is greater than the specified value Th2, the process proceeds to step 608, and otherwise, the process proceeds to step 606.

  According to the process shown in FIG. 6, the following effects can be obtained in addition to the effects of the process shown in FIG. By considering the detection level of the lateral distance of the object, the second driving force limit control and the intervention braking control can be permitted even for an object that is separated by a predetermined distance α or more. Thereby, it becomes possible to start the second driving force limit control and the intervention braking control at an earlier stage (even when the distance is greater than or equal to the predetermined distance α) with respect to the obstacle in the front direction, if necessary. .

  FIG. 7 is an explanatory diagram of the calculation principle of the lateral distance. In FIG. 7, the origin O corresponds to the center in the left-right direction of the front portion of the vehicle, S represents the position of the clearance sonar 201b, T represents the position of the clearance sonar 201a, and U represents the position of the object (reflection). Position). Here, the left clearance sonar 201b is focused as described above, but the same applies to the right clearance sonar 201a.

When the position of the object is located in the overlapping region D3 of the detection regions D1 and D2 of the clearance sonars 201a and 201b, when the clearance sonar 201b emits an ultrasonic wave, not only the clearance sonar 201b but also the clearance sonar 201b includes the clearance sonar 201b. It is possible to receive a reflected wave related to the ultrasonic wave transmitted by the. At this time, the following formula is established for the reflected wave received by the clearance sonar 201b.
2L ₁ = vt _SS formula (1)
Here, L ₁ is the distance from the clearance sonar 201b to the object, v is the speed of sound, and t _SS is the time (flight time) from the time of ultrasonic wave transmission to the time of reception of the reflected wave in the clearance sonar 201b. .
Similarly, the following equation holds for the reflected wave received by the clearance sonar 201a.
L ₁ + L ₂ = vt _ST formula (2)
Here, _{L 2} is the distance from the clearance sonar 201a to the _{object, t ST} is the time from the ultrasonic transmitter in the clearance sonar 201b until the reflected waves received in the clearance sonar 201a.
Moreover, the following formula | equation is materialized from geometric relationship.
(X + p) ² + y ² = L ₁ ² formula (3)
^{(X-p) 2 + y} 2 = L 2 2 Equation (4)
Here, p is a lateral distance (known) between the clearance sonars 201a and 201b and the origin. From these four equations, the lateral distance x of the object can be obtained.

  In this way, when the position of the object is located within the overlapping area D3 of the detection areas D1 and D2 of the clearance sonars 201a and 201b, the lateral distance x of the object can be calculated. Therefore, if the detection level of the lateral distance of the object is larger than the specified value Th2, it means that there is a high possibility that the object is located in the overlapping region D3. Using this point, according to the processing shown in FIG. 6, an object (an obstacle in the front direction) located in the overlapping region D3 is separated earlier (a predetermined distance α or more) as necessary. It becomes possible to start the second driving force limiting control and the intervention braking control (even when the driving force is limited).

  In the description with reference to FIG. 7, the reception result of the reflected wave related to the ultrasonic wave transmitted by the clearance sonar 201b and the reception result of the reflected wave related to the ultrasonic wave transmitted from the clearance sonar 201b in the clearance sonar 201a Is used to calculate the lateral distance x of the object, but other aspects are possible. For example, the reception result of the reflected wave related to the ultrasonic wave transmitted by itself in the clearance sonar 201b and the reception result of the reflected wave related to the ultrasonic wave transmitted from the clearance sonar 201b in the clearance sonar 201b are used. It is also possible to calculate the direction distance x.

  FIG. 8 is an explanatory diagram of an example of a method for calculating the detection level of the lateral distance of the object, (A) shows an example of a time series showing the detection state of the lateral distance, and (B) shows a timer value. (C) shows an example of a time series of detection levels.

  In the example shown in FIG. 8, the timer value is counted up while the lateral distance is detected, and is counted down while the lateral distance is not detected. The timer value has a lower limit value (initial value 0) and a predetermined upper limit value. The detection level is determined according to the timer value. In the example shown in FIG. 8, there are four detection levels from 0 to 3, and the threshold value in the direction in which the detection level increases and the threshold value in the direction in which the detection level decreases have hysteresis. For example, as shown in FIG. 8, the hysteresis may be set in such a manner that the threshold value in the direction in which the detection level increases is higher than the threshold value in the direction in which the detection level decreases.

  In the example shown in FIG. 8, a certain object starts to be detected at time t0. The detection state of the object is maintained until time t3. Accordingly, the timer value increases until time t3, with 0 at time t0 as an initial value. During this time, the timer value exceeds the threshold for increasing the detection level from 0 to 1 at time t1, and the detection level becomes 1. After that, the timer value exceeds the threshold for the detection level to increase from 1 to 2 at time t2, and the detection level becomes 2. The non-detection state of the object from time t3 is maintained until time t5. Along with this, the timer value gradually decreases. During this time, the timer value falls below the threshold for the detection level to drop from 2 to 1 at time t4, and the detection level becomes 1. At time t5, the same object starts to be detected again. The detection state of the object is maintained until time t8. Along with this, the timer value starts to rise again from time t5. The timer value reaches the upper limit value after time t7 and maintains the upper limit value until time t8 (the interval of the upper limit value is indicated by symbol M). During this time, the timer value exceeds the threshold for increasing the detection level from 1 to 2 at time t6, and the detection level becomes 2. After that, at time t7, the timer value exceeds the threshold for increasing the detection level from 2 to 3, and the detection level becomes 3 (maximum value). The non-detected state of the object from time t8 is maintained beyond time t10. Along with this, the timer value gradually decreases. During this time, the timer value falls below the threshold for the detection level to drop from 3 to 2 at time t9, and the detection level becomes 2. Thereafter, the timer value falls below the threshold for the detection level to drop from 2 to 1 at time t10, and the detection level becomes 1.

  When the method for calculating the detection level of the lateral distance of the object shown in FIG. 8 is used, the specified value Th2 in step 605 in FIG. 6 may be level 1 or level 2, for example. Alternatively, the determination in step 605 in FIG. 6 may be omitted (only the detection of the lateral distance detection level is performed), and the predetermined distance α may be varied in accordance with the lateral distance detection level. In this case, the predetermined distance α may be varied in such a manner that the predetermined distance α increases as the detection level of the lateral distance increases.

  In the examples shown in FIGS. 6 to 8, the detection level of the lateral distance of the object is calculated without considering the lateral distance value itself, but the lateral distance value may be considered. . For example, the detection level of the lateral distance of the object may be an index value that increases when a lateral distance of a predetermined distance or less is detected. In this case, the predetermined distance may be a value corresponding to half of the vehicle width, and a predetermined margin may be given. Such a configuration is suitable, for example, when the lateral width of the overlap region D3 is significantly larger than the vehicle width.

  Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes can be made within the scope described in the claims. It is also possible to combine all or a plurality of the components of the above-described embodiments.

  For example, the above description mainly relates to the left and right clearance sonars 201a and 201b for detecting the front object, but the same applies to the left and right clearance sonars 201c and 201d for detecting the rear object.

  In the embodiment described above, both the second driving force limiting control and the intervention braking control are executed, but only one of them may be executed.

  In the embodiment described above, the predetermined distance α is common to the second driving force limit control and the intervention braking control, but different values are used for the second driving force limitation control and the intervention braking control. May be. For example, with respect to Step 406 and Step 408 (or Step 606 and Step 608), the second driving force limit control is permitted when the target distance is smaller than a predetermined value β (≠ α), and the intervention braking control is performed. Permitted when the target distance is smaller than the predetermined value α.

  In the processing shown in FIGS. 4 and 6, as a preferred embodiment, the object detection level is considered (step 404, step 604), but the object detection level may not be considered. That is, in the processes shown in FIGS. 4 and 6, the processes of Step 404 and Step 604 may be omitted.

  In the processing shown in FIGS. 4 and 6, if a negative determination is made in step 404 and step 604, the first driving force limiting control and the second driving force are the same as in the case where a negative determination is made in step 402 and step 602. Although all of the limit control and the intervention brake control are prohibited, even if a negative determination is made in step 404 and step 604, the drive force limit control having a lower limit than the first drive force limit control is permitted. Good.

  The processing shown in FIGS. 4 and 6 is executed in a low speed region where the vehicle speed is greater than 0 and less than or equal to a predetermined vehicle speed as a preferred embodiment, but is executed in a medium speed region or the like exceeding the predetermined vehicle speed. May be.

  In the processing shown in FIG. 6, the object detection level (step 604) and the lateral distance detection level (step 605) are individually evaluated, but may be comprehensively evaluated. . For example, the predetermined distance α may be varied according to an index value obtained by combining (for example, simply adding) these detection levels.

1 Driving assistance device 10 Driving assistance ECU
20 Crisona ECU
30 G sensor 40 Rudder angle sensor 50 Meter computer 60 Engine ECU
70 Brake ECU
DESCRIPTION OF SYMBOLS 101 Input processing part 102 Vehicle state estimation part 103 Obstacle determination part 104 Control amount calculating part 105 HMI calculating part 106 Output processing part 201a-201d Clearance sonar

Claims (6)

An ultrasonic sensor that transmits an ultrasonic wave toward an object outside the vehicle, and acquires object information related to a distance to the object based on the reflected wave;
When the distance to the object is greater than or equal to a predetermined distance based on the object information from the ultrasonic sensor, the first driving force restriction control is permitted, while the distance to the object is smaller than the predetermined distance Comprises a processing device that permits at least one of the second driving force limiting control and the intervention braking control that are higher in the degree of limitation than the first driving force limiting control. The first driving force limit control is a control for setting a predetermined upper limit value for the driving force request calculated according to the accelerator operation by the user,
2. The driving support device according to claim 1, wherein the second driving force limiting control is control for fully closing a throttle opening degree according to a distance to the object and a vehicle speed of the host vehicle.   The driving support device according to claim 1, wherein the predetermined distance is set in accordance with a width between side walls existing on both sides of a road that can be passed. A plurality of the ultrasonic sensors are provided,
The processing device acquires lateral distance information related to a lateral distance of the object based on the traveling direction of the host vehicle based on the object information from the plurality of ultrasonic sensors,
When the first index value indicating how long the lateral distance information has been acquired is greater than or equal to a predetermined first reference value, the processing apparatus determines that the distance to the object is the predetermined distance The driving support device according to any one of claims 1 to 3, wherein at least one of the second driving force limiting control and the intervention braking control is permitted even when the distance is equal to or longer than a distance.   When the second index value indicating how long the object is detected based on the object information from the ultrasonic sensor is greater than or equal to a predetermined second reference value, the processing device 5. The apparatus according to claim 1, wherein at least one of the first driving force limit control, the second driving force limit control, and the intervention braking control is permitted. Driving assistance device.   The processing device permits at least one of the first driving force limiting control, the second driving force limiting control, and the intervention braking control only when the vehicle speed of the host vehicle is smaller than a predetermined vehicle speed. The driving support device according to any one of claims 1 to 5.

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